The police service sometimes explicitly clears people once linked to crime probes. In the Project Traveller case, Ford has not been so lucky.

Toronto Police Chief Bill Blair speaks at a news conference on June 13 in which he avoided answering questions about the potential involvement of Mayor Rob Ford in the Project Traveller investigation, saying any and all evidence in the case would come out in court, and not before.

Toronto police have been tight-lipped about whether Mayor Rob Ford has any connection to a criminal investigation pushed into the limelight after a series of raids targeting guns, gangs and drugs earlier this month.

But people connected to criminal investigations have often had their names cleared and their innocence assured at public news conferences and in statements by detectives, following further investigation by police.

Police spokesperson Mark Pugash said several examples of such cases found by the Star were “fundamentally different” from this one, but would not elaborate how.

At two public appearances — one to update reporters on the so-called Project Traveller investigation that netted 44 arrests of alleged gang members in a guns-and-drugs smuggling ring — Police Chief Bill Blair refused to answer questions about the mayor’s potential involvement, whether there is a criminal investigation in the mayor’s office or whether police had recovered a video appearing to show the mayor smoking crack cocaine.

After legal experts told the Star that Blair could disclose information about the mayor’s involvement, Blair told reporters he had received legal advice from the attorney general’s office, but has not elaborated on what specific rules he is following.

“If you look in the Criminal Code and the Police Services Act, there are very specific sections in there that define exactly what the responsibilities and the authorities of the police are to disclose information, and I am following that law to the letter,” Blair said last week.

Police officials have refused to direct the Star to specific sections in the Criminal Code or the Police Service Act that stop Blair from clearing the mayor.

The Star found several high-profile and other examples over the past five years in which Toronto and Hamilton investigators publicly cleared the names of people who were once “persons of interest,” suspects, or whose involvement in criminal investigations was questioned by the media:

In 2008, the Toronto Police homicide squad was investigating a triple murder after three men were discovered shot dead inside an SUV in Etobicoke. Police were initially looking for the driver of the SUV, who was not found at the scene. But later, Det.-Sgt. Frank Skubic told reporters the driver, who had escaped unharmed, was believed to also be a victim. “We have nothing to suggest the driver is the killer,” reporters were told.

Police also cleared the registered owner of the SUV as having any involvement.

Later in 2008, the Toronto Police homicide squad was investigating a triple murder-suicide at a Scarborough family home, in which a man had allegedly killed his wife and two adult children before killing himself. Police at first believed the husband of one of the women killed, James Tompkins, to be a suspect and arrested him. But later, at a news conference, Det.-Sgt. Pauline Gray told reporters that Tompkins was no longer a suspect and had been the one to call 911.

In 2009, Toronto Police questioned Bartosz Gajewski in connection with the disappearance of Toronto teen Mariam Makhniashvili, after he was arrested in what was thought to be a similar case. Police later publicized the fact that he was not considered a suspect in the Makhniashvili case.

In 2010, Toronto Police were seeking a man in the death of a 5-month-old baby he was alleged to have babysat and then assaulted. The baby was brought to a local hospital with obvious injuries and eventually died. Det.-Sgt. Colin Greenaway told reporters that the mother of the child was not involved in the case.

In May of this year, the lead Hamilton Police investigator in the Tim Bosma murder cleared a known friend of accused Dellen Millard — whose name is currently protected by a publication ban.

“He’s been interviewed and he’s been cleared as having involvement,” Det.-Sgt. Matt Kavanagh told reporters at a news conference. Later, Kavanagh told a Star reporter that Millard’s girlfriend also had no involvement in the death.

When asked why the police commented on involvement, or lack of it, in those situations, but not the mayor’s potential involvement in the recent sweep, Pugash said “they are not applicable in any way,” and referred a reporter to Blair’s previous statements to media.

He added he would not comment on investigations conducted by another police agency.

Ford has been linked to the project after sources told the Star the mayor blurted out to staff the address of a unit on Dixon Rd. where he said the video could be found — an address later raided by police.

Sources also told the Star that police learned of the video while conducting surveillance for Project Traveller.

And a photo given to the Star shows the mayor posing with three men — one of whom was shot dead earlier this year, and two others who were arrested as part of the operation. The house where the photo is believed to have been taken was also subject to a search warrant as part of Project Traveller.

Ford has said he does not smoke crack and has denied the existence of a video seen by two Star reporters.